In recent years, digital cameras (image sensing devices) which can sense an image and can convert the sensed image into digital image data by a simple operation have been popularly used. When an image sensed by such camera is printed and is used as a photograph, it is a common practice to temporarily download the sensed digital image data from a digital camera to a PC (computer), to execute an image process by that PC, and to output the processed image data from the PC to a color printer, thus recording an image.
By contrast, a color print system which allows a digital camera to directly transfer digital image data to a color printer without the intervention of any PC and can print it out (to be referred to as a direct print process hereinafter), a so-called photo-direct (PD) printer which can receive a memory card, which is mounted on a digital camera and stores sensed images, and can print sensed images, and the like have recently been developed (see Japanese Patent Laid-Open No. 2003-061034).
As the memory size of such memory card increases, a large number of image files can be stored in a single memory card, but it becomes difficult to confirm correspondence between image files and memory cards that store them. For this reason, of DP printers, models that can output index prints like those which are attached upon making additional prints of silver halide photographs are increasing. An index print is a print of a list of thumbnail images of image files stored in a memory card, and is used for the purpose of confirming and selecting images to be actually printed rather than a print which is used to appreciate and enjoy images. Therefore, upon making an index print, identifiers (e.g., numbers and the like) are appended to respective images. Also, upon making an index print, a maximum number of images which can be printed by a printer on a single recording medium (sheet) are normally printed.
However, a conventional index print allows the user to confirm what kind of image it is but does not allow him or her to confirm the image quality since the size of each image is too small. For example, only after an image confirmed on an index print is printed in a large size (e.g., a standard L size), the user often finds that the image is out of focus, it has abnormal color tincture, and so forth. As a result, not only labor required to print but also inks and a sheet required to print the image are wasted. Such problem can be solved if the size of each index image is increased. However, as described above, since the memory card has a large memory size and stores a very large number of images, the need for recording many images (increasing the number of frames to be printed) and confirming many images at once has arisen so as to efficiently confirm a large number of images stored in the memory card.
On the other hand, in order to print a large number of index images per sheet, a printer must have a huge memory size for storing these image data. Hence, the maximum number of index images that can be printed largely depends on the manufacturing cost of a printer. Under the present circumstances, the maximum number of images per sheet in an index print equals the maximum number of images that can be printed by a printer. For example, when an A4-size index print is to be made, the number of index images on the print often falls within the range from about 60 to 100.